Heat a large pot or Dutch oven over medium heat. Add olive oil, then once hot, add the diced onions and sauté for 2 minutes until softened. Add minced garlic and cook for an additional 30 seconds to release aroma.

Add the ground turkey to the pot. Cook until no longer pink, breaking it into smaller chunks with a spoon, for about 4 to 6 minutes.

Sprinkle in chili seasoning and pumpkin pie spice, stirring to coat the meat evenly. Cook for 1 minute to bloom the spices. Add tomato paste, stir well, and continue cooking for 1 minute. Then add diced red bell peppers and minced jalapenos, cooking for another minute to soften.

Pour in the kidney beans, black beans, pinto beans, pumpkin puree, crushed tomatoes, fire-roasted tomatoes with their juice, chicken stock, and Worcestershire sauce. Stir everything together until fully combined.

Bring the mixture to a boil, then reduce the heat to medium to maintain a gentle simmer. Stir occasionally and cook until the chili thickens slightly and the flavors meld, about 25 to 30 minutes. Adjust heat if bubbling too rapidly, and add more stock or water if you prefer a thinner consistency. Season with salt and pepper to taste.

Ladle the chili into bowls and top with your choice of sour cream, shredded cheddar cheese, pepitas, and sliced green onions for garnish.